PHENOTYPING AND OUTCOMES CORE (POC) The University of Michigan Fibromyalgia CORT proposes that presence of centralized pain will render individuals less responsive to analgesic therapies aimed at peripheral/nociceptive pain (surgery, biologics, opioids) and that this centralized pain phenotype has stereotypical clinical and neurobiological features similar to FM even when it is co-morbid with other musculoskeletal pain conditions with disparate underlying pain mechanisms. The Specific Aims of the CORT supported by the POC are as follows: 1) To demonstrate that the current 2011 FM Survey Criteria serve as a strong surrogate of pain centralization and strongly predict non- responsiveness to therapies generally effective for treating peripherally-based pain, including a) surgery intended to relieve pain (hip arthroplasty, carpal tunnel release), b) administration of a biologic agent to treat an autoimmune disorder (rheumatoid arthritis), and c) acute perioperative administration of opioids; 2) To demonstrate that in all three cohorts individuals with the highest FM scores will have similar neurobiological findings of pain centralization on quantitative sensory testing (QST) and neuroimaging; 3) To develop and pilot test a shorter and more predictive self-report measure of pain centralization; and 4) To explore the clinical and mechanistic features of two important subsets of centralized pain: top-down (i.e. previously termed primary FM) vs. bottom-up (i.e. previously termed secondary FM). Specifically, the POC will be responsible for the following: (1) Assessment of treatment outcomes for each treatment cohort, (2) Phenotyping/characterization of each patient cohort, the FM control group, and the healthy control group, (3) Development of a latent construct of centralized pain based upon self-report, QST, and neuroimaging findings, (4) Development and validation of a new clinically applicable measure of centralization, and (5) Exploration of two potential subtypes of centralization along with the development of self-report items that may assess those subtypes.